Heat dissipator for optical writing and/or reproducing apparatus

ABSTRACT

Disclosed is a heat dissipator for an optical writing and/or reproducing apparatus. The heat dissipator comprises a main base having mounted thereto a plurality of parts including at least one motor for optical writing and/or reproduction; a circuit board positioned below the main base and having installed thereon elements for controlling the parts; a heat generating element formed with a plurality of leads which are connected to a circuit pattern of the circuit board; a heat conduction member brought into contact with at least the leads, for receiving heat generated in the heat generating element; and a cabinet brought into contact with the heat conduction member and formed with an element accommodating section and/or a pair of protrusions which are shaped to be functionally associated with an outer surface of the heat generating element to ensure that the heat dissipating member is brought into close contact with the leads of the heat generating element.

This application is a continuation of application Ser. No. 10/141,814,filed on May 10, 2002, now U.S. Pat. No. 6,603,659 the entire contentsof which are hereby incorporated by reference and for which priority isclaimed under 35 U.S.C. § 120; and this application claims priority ofapplication Ser. No. 25587/2001 filed in Korea on May 10, 2001 under 35U.S.C. § 119.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a heat dissipator for an opticalwriting and/or reproducing apparatus, and more particularly, the presentinvention relates to a heat dissipator for an optical writing and/orreproducing apparatus, which is constructed to properly dissipate heatgenerated in a heat generating element, especially, a drive IC(integrated circuit) while the optical writing and/or reproducingapparatus is driven.

2. Description of the Related Art

Generally, in an optical writing and/or reproducing apparatus such as adisk drive, a great amount of heat is generated during operation. In anoptical writing and/or reproducing apparatus, heat generating partsinclude a loading motor for producing power needed to load and eject anoptical disk, a spindle motor for rotating the optical disk, an opticalpick-up for writing and/or reproducing data on and/or from the opticaldisk, a step motor for driving the optical pick-up, and elementsinstalled on a circuit board for controlling operation of the opticalwriting and/or reproducing apparatus.

If generated heat is not properly dissipated out of the optical writingand/or reproducing apparatus, not only the corresponding heat generatingsource but also surrounding parts can be adversely affected by the heat,and thereby, an operational error can be caused in the optical writingand/or reproducing apparatus.

Specifically, among the elements installed on the circuit board forcontrolling operation of the optical writing and/or reproducingapparatus, a drive IC for controlling driving of the motors generates asubstantial amount of heat when compared to the other elements.

FIG. 1 is a cross-sectional view illustrating a conventional heatdissipator for an optical writing and/or reproducing apparatus.

Referring to FIG. 1, an optical writing and/or reproducing apparatusincludes a main base 30, and a circuit board 40 positioned below themain base 30. Elements for controlling operation of the optical writingand/or reproducing apparatus are installed on the circuit board 40. Aspindle motor, a loading motor and a step motor (not shown) areinstalled on the main base 30.

Among the elements installed on the circuit board 40, since a drive IC42 continuously controls driving of the motors, it consumes a largeamount of power and thereby generates a substantial amount of heat whencompared to the other elements. For this reason, the drive IC 42 isinstalled on a lower surface 40 b of the circuit board 40 so as not toadversely influence, by heat, surrounding elements including an RF(radio frequency) IC and a DSP (digital signal processor) IC which areinstalled on an upper surface 40 a of the circuit board 40. At thistime, the drive IC 40 is installed in a manner such that outer leads 43externally formed thereon are bonded to the lower surface 40 b of thecircuit board 40.

Hereafter, the conventional heat dissipator for dissipating heatgenerated in the drive IC 42 will be described in detail.

The heat dissipator includes a lower cabinet 51 b which is positioned toface the lower surface 40 b of the circuit board 40 and a heatdissipating conduction member 54 which is interposed between the lowercabinet 51 b and a molding section 42 a of the drive IC 42. The lowercabinet 51 b delimits an outer contour of the optical writing and/orreproducing apparatus and is made of a metallic material. The heatconduction member 54 functions to dissipate or conduct the heatgenerated in the drive IC 42. Over a region where the lower cabinet 51 bfaces the molding section 42 a of the drive IC 42, the lower cabinet 51b is formed with an upward protrusion 51 c which projects toward thedrive IC 42 to allow the heat dissipating conduction member 54 to bebrought into close contact with the molding section 42 a of the drive IC42.

At this time, the heat conduction member 54 is not brought into contactwith the outer leads 43 which serve to connect the drive IC 42 to thecircuit board 40.

Concretely speaking, between the drive IC 42 installed on the lowersurface 40 b of the circuit board 40 and the lower cabinet 51 b facingthe drive IC 42, there is interposed the heat conduction member 54 in amanner such that it is brought into close contact with the moldingsection 42a of the drive IC 42. As a consequence, heat generated in themolding section 42 a of the drive IC 42 is transmitted through the heatconduction member 54 to the lower cabinet 51 b to be dissipated to theoutside.

However, the conventional heat dissipator constructed as mentioned abovesuffers from defects as described below.

While heat generated inside the drive IC 42 is first conducted to amolding material, that is, the molding section 42 a serving as anencapsulant, and then transmitted to the lower cabinet 51 b, in actualfact, since a considerable portion of the heat generated inside thedrive IC 42 is conducted to the outer leads 43 made of a metallicmaterial, the outer leads 43 have a higher temperature than the moldingmaterial. Resultingly, as heat of the outer leads 43 is transmitted to acircuit pattern formed on the circuit board 40, the circuit pattern islikely to be thermally damaged.

Also, because the heat conduction member 54 is installed over the regionwhich faces only a lower surface of the molding section 42 a of thedrive IC 42, heat of side surfaces of the drive IC 42 and heat of theouter leads 43 cannot be properly conducted to the heat dissipatingconduction member 54. Therefore, heat as a whole, generated in theentire drive IC 42, cannot be properly transmitted to the lower cabinet51 b.

The reason for this is that only heat of the lower surface of themolding section 42 a of the drive IC 42 is conducted to the heatconduction member 54 to be dissipated to the outside, and heat of theside surfaces of the drive IC 42 and heat of the outer leads 43 aredissipated to the outside only by convection through air.

SUMMARY OF THE INVENTION

Accordingly, the present invention has been made in an effort to solvethe problems occurring in the related art, and an object of the presentinvention is to provide a heat dissipator for an optical writing and/orreproducing apparatus, which is constructed to properly dissipate heatgenerated in the optical writing and/or reproducing apparatus, therebyimproving operational reliability of the optical writing and/orreproducing apparatus.

According to one aspect of the present invention, there is provided aheat dissipator for an optical writing and/or reproducing apparatus,comprising: a main base having mounted thereto a plurality of partsincluding at least one motor for optical writing and/or reproduction; acircuit board positioned below the main base and having installedthereon elements for controlling the parts; a heat generating elementformed with a plurality of leads which are connected to a circuitpattern of the circuit board; a heat conduction member brought intocontact with at least the leads, for receiving heat generated in theheat generating element; and a cabinet brought into contact with theheat conduction member and formed with an element accommodating sectionand/or a pair of protrusions which are shaped to be functionallyassociated with an outer surface of the heat generating element toensure that the heat conduction member is brought into close contactwith the leads of the heat generating element.

According to another aspect of the present invention, there is provideda heat dissipator for an optical writing and/or reproducing apparatus,comprising: a heat generating element installed on a circuit board andhaving a molding section which is formed with a plurality of leadsconnected to a circuit pattern of the circuit board; a cabinet formedwith a pair of protrusions which project toward the heat generatingelement to allow a portion of heat generated in the heat generatingelement, which portion is conducted to the leads, to be dissipated tothe outside; and a heat conduction member interposed between the cabinetand the heat generating element and brought into contact with at leastthe leads and/or the pair of projections.

According to still another aspect of the present invention, there isprovided a heat dissipating structure adapted for dissipating heatgenerated in an optical writing and/or reproducing apparatus,comprising: a heat generating element having a molding section which isformed with a plurality of leads; a cabinet formed with an elementaccommodating section for accommodating the heat generating element anda pair of protrusions which delimit the element accommodating section;and a heat conduction member interposed between the heat generatingelement and the cabinet, for being brought into contact with the leadsand the molding section and at the same time the element accommodatingsection and the pair of protrusions, whereby heat of the leads istransmitted to the protrusions to enhance a heat dissipation efficiency.

As described above, in the heat dissipator for an optical writing and/orreproducing apparatus according to the present invention, an elementaccommodating section is formed on a lower cabinet in a manner such thatit is functionally associated with outer surfaces and outer leads of aheat generating element, and a heat conduction member is interposedbetween the element accommodating section and the heat generatingelement.

Hence, according to the present invention, advantages are provided inthat, since heat is transmitted from the outer surfaces, that is, alower surface and both side surfaces and the outer leads of the heatgenerating element to the heat conduction member, and dissipated throughthe lower cabinet to the outside, heat as a whole, generated in the heatgenerating element, can be properly dissipated to the outside. Also,because performance degradation of the heat generating element andsurrounding parts due to overheating is prevented, operationalreliability of the optical writing and/or reproducing apparatus can beimproved.

Further, in the present invention, due to the fact that a size of theheat dissipating member is increased to be able to cover the entiredrive IC including the outer leads, a heat dissipation efficiency isenhanced.

BRIEF DESCRIPTION OF THE DRAWINGS

The above objects, and other features and advantages of the presentinvention will become more apparent after a reading of the followingdetailed description when taken in conjunction with the drawings, inwhich:

FIG. 1 is a cross-sectional view illustrating a conventional heatdissipator for an optical writing and/or reproducing apparatus;

FIG. 2 is an exploded perspective view illustrating an optical writingand/or reproducing apparatus in which a heat dissipator in accordancewith an embodiment of the present invention is used; and

FIG. 3 is a cross-sectional view illustrating the heat dissipatoraccording to the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Reference will now be made in greater detail to a preferred embodimentof the invention, an example of which is illustrated in the accompanyingdrawings. Wherever possible, the same reference numerals will be usedthroughout the drawings and the description to refer to the same or likeparts.

FIG. 2 is an exploded perspective view illustrating an optical writingand/or reproducing apparatus in which a heat dissipator in accordancewith an embodiment of the present invention is used. In the presentinvention, the parts that correspond to those of FIG. 1 will bedesignated by the same reference numerals.

Describing in detail, with reference to FIG. 2, a construction of anoptical writing and/or reproducing apparatus which adopts a heatdissipator in accordance with an embodiment of the present invention,the optical writing and/or reproducing apparatus includes a pick-up base(not shown) serving as a frame. A spindle motor for rotating an opticaldisk and an optical pick-up for radiating light to write and/orreproduce data on and/or from the optical disk are installed on thepick-up base. The optical writing and/or reproducing apparatus furtherincludes a main base 30, a circuit board 40, a drive IC 42, a pluralityof outer leads 43, upper and lower cabinets 51 a and 51 b, and a heatconduction member 54 55. A tray 34 for loading and ejecting the opticaldisk into and from the optical writing and/or reproducing apparatus isarranged on the main base 30. The circuit board 40 is positioned belowthe main base 30, and a variety of elements for driving the spindlemotor, the optical pick-up, etc. are installed on the circuit board 40.The drive IC 42 is installed on a lower surface of the circuit board 40to face an upper surface of the lower cabinet 51 b. The plurality ofouter leads 43 project out of both side surfaces of the drive IC 42 andare bonded to the circuit board 40 by soldering. The upper and lowercabinets 51 a and 51 b which constitute a cover 50 delimit an outercontour of the optical writing and/or reproducing apparatus and are madeof a metallic material. The heat conduction member 54 55 functions totransmit heat generated in the drive IC 42 to the lower cabinet 51 bthereby to dissipate the heat to the outside.

Describing in further detail the construction of the optical writingand/or reproducing apparatus which adopts the heat dissipator inaccordance with the embodiment of the present invention, an uppersurface 35 of the tray 34 serves as a disk seating surface on which theoptical disk is seated upon being loaded and ejected. A clamp 36 isdisposed above the tray 34 to clamp the optical disk to a turntable (notshown) provided to the spindle motor.

A connection socket 45 for permitting connection of the optical writingand/or reproducing element to another unit is installed at one end ofthe circuit board 40. The upper cabinet 51 a defines an upper surfaceand both side surfaces of the optical writing and/or reproducingapparatus, and the lower cabinet 51 b defines a lower surface of theoptical writing and/or reproducing apparatus. However, it is to bereadily understood that the present invention is not limited to such astructure, and the lower cabinet 51 b can define a lower surface andboth side surfaces of the optical writing and/or reproducing apparatus.

Generally, a rear surface of the optical writing and/or reproducingapparatus is defined by the main base 30, and a front surface is definedby a separate front plate (not shown).

According to the present invention, over a region where the lowercabinet 51 b faces the drive IC 42, the lower cabinet 51 b is formedwith an element accommodating section 52. The element accommodatingsection 52 defines a space which can accommodate therein the entiredrive IC 42. The element accommodating section 52 has a size which islarger than a width of the drive IC 42. The element accommodatingsection 52 is delimited by a pair of protrusions 53 which project towardthe circuit board 40 at left and right sides of the elementaccommodating section 52. The pair of protrusions 53 are formed in amanner such that they face the outer leads 43 of the drive IC 42. In theillustrated embodiment, the drive IC 42 has a body which possesses aparallelepiped-shaped configuration, and the plurality of outer leads 43which project outward from both side surfaces of the body. At this time,a lower surface and both side surfaces of the body of the drive IC 42and the outer leads 43 projecting out of both side surfaces of the driveIC 42 are functionally associated with the upper surface of the lowercabinet 51 b.

The element accommodating section 52, which is associated with the lowersurface of the body of the drive IC 42, is formed to have the sameheight as a remaining portion of the lower cabinet 51 b. And, the pairof protrusions 53, which are associated with the outer leads 43, projecttoward the circuit board 40 to extend upward beyond the lower surface ofthe body of the drive IC 42.

The heat conduction member 55 is made of soft silicon such as GAP PAD™manufactured by BERGQUIST or Raychem™ manufactured by Tyco.

FIG. 3 is a cross-sectional view illustrating the heat dissipatoraccording to the present invention.

The construction of the heat dissipator according to the presentinvention will be described below in further detail with reference toFIG. 3.

The heat conduction member 54 55 is attached to the drive IC 42 which isinstalled on the lower surface of the circuit board 40. The heatconduction member 54 55 is made of a soft material and therefore can befreely deformed. A size of the heat conduction member 54 55 isdetermined in a manner such that it can be brought into sufficientcontact with the lower surface and the outer leads 43 of the drive IC42. Then, by assembling the lower cabinet 51 b with respect to the heatconduction member 54 55, the body of the drive IC 42 is accommodated inthe element accommodating section 52, and the pair of protrusions 53bias the heat conduction member 54 55 to be brought into close contactwith the outer leads 43.

Hereafter, working effects of the heat dissipator for an optical writingand/or reproducing apparatus according to the present invention,constructed as mentioned above, will be described in detail.

While the optical writing and/or reproducing apparatus is operated, heatis generated in a number of parts. The generated heat should be properlydissipated to the outside to prevent the corresponding heat generatingsource and surrounding parts to be adversely affected by the heat. Inthe optical writing and/or reproducing apparatus, heat generating partsinclude the optical pick-up, the spindle motor, a step motor, and thevariety of elements including the drive IC 42.

The present invention is focused on dissipation of heat generated in thevariety of elements including the drive IC 42. Description of thepresent embodiment will be given mainly in relation with the drive IC42. While the optical disk is driven, a considerable amount of heat isgenerated in the drive IC 42 installed on the circuit board 40. Thegenerated heat is partially dissipated to the outside through the lowersurface and both side surfaces of the drive IC 42 and is partiallyconducted to the outer leads 43 made of a metallic material.

The heat conduction member 55, which is located in the elementaccommodating section 52 to be functionally associated with the lowersurface and the outer leads 43 of the drive IC 42, is brought intocontact with the lower surface and the outer leads 43 of the drive IC42. Therefore, as the heat conduction member 55 receives heat from thelower surface and the outer leads 43 of the drive IC 42 and transmitsthe heat to the lower cabinet 51 b, the heat is dissipated to theoutside through the lower cabinet 51 b.

That is to say, heat generated in the drive IC 42 is transmitted throughits entire outer surface and the outer leads 43 to the heat conductionmember 55. Accordingly, almost all of the heat generated in the drive IC42 can be transmitted to the heat conduction member 55.

Experimental temperature data obtained by the heat dissipators accordingto the present invention and the conventional art, respectively, arepresented below in TABLE 1.

TABLE 1 Conventional Present lower cabinet lower cabinet Optical pick-up63° C. 62° C. Spindle motor 69° C. 72° C. Step motor 71° C. 74° C. DSPIC 75° C. 76° C. RF IC 83° C. 84° C. Drive IC 102° C.  86° C. Lowercabinet 60° C. 63° C. Internal Space 47° C. 46° C.

As can be readily seen from TABLE 1, in the case that the lower cabinetstructure according to the present invention is applied to the heatdissipator, the drive IC 42 which usually has a highest temperature inan optical writing and/or reproducing apparatus is significantly reducedin its temperature to 86° C. when compared to its temperature of 102° C.under the conventional art. Further, a temperature of the lower cabinet51 b is slightly increased from 60° C. to 63° C. As a result, a personskilled in the art will readily recognize that, in the presentinvention, heat generated in the drive IC 42 is properly transmitted tothe lower cabinet 51 b through the heat conduction member 55 anddissipated to the outside.

Of course, it is to be noted that the heat dissipator according to thepresent invention can be employed not only in the drive IC but alsoother heat generating elements which are installed on the circuit board.

Preferably, the heat dissipating member comprises a heat dissipatingpad.

More preferably, the heat dissipating pad is made of a suitable materialsuch as silicon.

In the preferred embodiment of the present invention, as a heatgenerating element, the drive IC which is formed at both side surfacesthereof with the plurality of leads, was described. However, the presentinvention is not limited to this configuration of the drive IC, and itis possible to use a drive IC which is formed, at its four sidesurfaces, with leads. In this case, it is to be understood that fourprotrusions must be formed on the lower cabinet 51 b.

As described above, in the present invention, since heat of the lowerand side surfaces and the outer leads 43 of the drive IC 42 serving as aheat generating element in the optical writing and/or reproducingapparatus is transmitted to the heat conduction member 55 and dissipatedto the outside through the lower cabinet 51 b, proper heat dissipationis ensured.

Thus, because performance degradation of the heat generating element andsurrounding parts due to overheating is prevented, operationalreliability of the optical writing and/or reproducing apparatus can beimproved.

Moreover, due to the fact that the element accommodating section 52 isformed to have the same height as the remaining portion of the lowercabinet 51 b, the entire height of the optical writing and/orreproducing apparatus can be decreased.

In the drawings and specification, there have been disclosed typicalpreferred embodiments of the invention and, although specific terms areemployed, they are used in a generic and descriptive sense only and notfor purposes of limitation, the scope of the invention being set forthin the following claims.

What is claimed:
 1. A heat dissipator for an electrical apparatus,comprising: a circuit board having installed thereon elements forcontrolling parts; a heat generating element formed with a plurality ofleads which are connected to a circuit pattern of the circuit board; aheat conduction member brought into contact with at least the leads, forreceiving heat generated in the heat generating element; and a cabinetbrought into contact with the heat conduction member and formed with anelement accommodating section and/or a pair of protrusions which areshaped to be functionally associated with an outer surface of the heatgenerating element to ensure that the heat conduction member is broughtinto close contact with the leads of the heat generating element.
 2. Theheat dissipator as set forth in claim 1, wherein the heat conductionmember is made of soft silicon.
 3. The heat dissipator as set forth inclaim 1, wherein the heat generating element comprises a drive IC. 4.The heat dissipator as set forth in claim 1, wherein the heat conductionmember is simultaneously brought into contact with a molding section andthe leads of the heat generating element, and the element accommodatingsection and/or the pair of protrusions enable the heat conduction memberto be brought into close contact with the molding section and the leadsof the heat generating element.
 5. The heat dissipator as set forth inclaim 1, wherein the leads are formed at side surfaces of the heatgenerating element.
 6. A heat dissipator for an electrical apparatus,comprising: a heat generating element installed on a circuit board ofthe electrical apparatus and having a molding section which is formedwith a plurality of leads connected to a circuit pattern of the circuitboard; a cabinet formed with a pair of protrusions which project towardthe heat generating element to allow a portion of heat generated in theheat generating element, which portion is conducted to the leads, to bedissipated to the outside; and a heat conduction member interposedbetween the cabinet and the heat generating element and brought intocontact with at least the leads and/or the pair of projections.
 7. Theheat dissipator as set forth in claim 6, wherein the heat conductionmember is made of soft silicon.
 8. The heat dissipator as set forth inclaim 6, wherein the heat generating element comprises a drive IC. 9.The heat dissipator as set forth in claim 6, wherein the cabinet isformed with an element accommodating section which enables the heatconduction member to be brought into close contact with the moldingsection of the heat generating element.
 10. The heat dissipator as setforth in claim 6, wherein the leads are formed at side surfaces of theheat generating element.
 11. A heat dissipating structure adapted fordissipating heat generated in an electrical apparatus, comprising: aheat generating element on the electrical apparatus having a moldingsection which is formed with a plurality of leads; a cabinet formed withan element accommodating section for accommodating the heat generatingelement and a pair of protrusions which delimit the elementaccommodating section; and a heat conduction member interposed betweenthe heat generating element and the cabinet, for being brought intocontact with the leads and the molding section and at the same time theelement accommodating section and the pair of protrusions, whereby heatof the leads is transmitted to the protrusions to enhance a heatdissipation efficiency.
 12. The heat dissipating structure as set forthin claim 11, wherein the heat conduction member is made of soft silicon.13. The heat dissipating structure as set forth in claim 11, wherein theheat generating element comprises a drive IC.
 14. The heat dissipatingstructure as set forth in claim 11, wherein the heat conduction membercomprises a heat dissipating pad.
 15. The heat dissipating structure asset forth in claim 11, wherein the leads are formed at side surfaces ofthe heat generating element.
 16. A heat dissipator for an electricalapparatus, comprising: a circuit board positioned having installedthereon elements for controlling parts; a heat generating element formedwith a plurality of leads which are connected to a circuit pattern ofthe circuit board and producing heat during operation; a heat conductionmember brought into contact with at least the leads, for receiving heatgenerated in the heat generating element; and a cabinet contact with theheat conduction member and having at least one protrusion to ensure thatthe heat conduction member being closely contacted with the leads of theheat generating element.
 17. The heat dissipator as set forth in claim16, wherein the heat conduction member is made of soft silicon.
 18. Theheat dissipator as set forth in claim 16, wherein the cabinet is formedwith an element accommodating section which enables the heat conductionmember to be contacted with a molding section of the heat generatingelement.
 19. The heat dissipator as set forth in claim 16, wherein theleads are formed at side surfaces of the heat generating element.